The present invention relates to stable aqueous colloidal dispersions of sulfonated polyurethane ureas and self-supporting films formed from these dispersions. After formation of the sulfonated polyurethane urea, alcohols can be added to the aqueous dispersion to provide a water-alcohol system. The films of the present invention are minimally tacky and self-adhesive.
Polyurethanes are a well-established class of high performance polymers, which can be readily tailored to display unique combinations of tensile strength, toughness, and flexibility. As a result of this versatility, polyurethanes have found utility in a variety of applications including binder resins, abrasion resistant coatings, protective coatings, and membranes.
Polyurethanes may be delivered to a substrate in one of three ways: i) extruded as a melt processable thermoplastic or thermoset material, ii) delivered as a moisture curable or two part curable system, generally from an organic solvent, or iii) delivered as an aqueous dispersion of a colloidal polymer system. Two part polyurethanes are generally used in binder or coating applications where they are delivered either from mixtures of organic solvents, blocked isocyanate terminated compounds, and diamine curatives, or mixtures of organic solvents, a diisocyanate terminated compound and polyols.
Aqueous polyurethane dispersions are utilized when high performance polyurethane properties are required but where volatile organic chemicals are not desirable. They offer advantages in that they have reduced volatile organic compound (VOC) emissions; they may eliminate exposure to toxic isocyanate or diamine compounds during coating; and they provide simplified overall processing. Aqueous polyurethane dispersions have been developed commercially as a means to deliver polyurethane coatings to a wide variety of substrates, including, for example, fibers, textiles, paper, films, wood, and concrete.
WO 99/05192 discloses aqueous colloidal dispersions of sulfopolyureas, comprising a high content of hard segments derived from aromatic diisocyanates, and films formed from these dispersions. The films have improved thermal stability and thus, improved high temperature performance, and may be used to form heat resistant abrasive articles. They are not redispersible in water.
U.S. Pat. No. 4,307,219 describes linear polyurethane resins that are prepared in an inert organic solvent under essentially anhydrous conditions and that once coated and dried, can be redispersed in water and aqueous organic solvents.
U.S. Pat. No. 4,738,992 describes a water-absorbing sponge comprising at least one of a pendant sulfo-group containing polyurea and polyurethane. The sponge comprises the reaction product of an isocyanate-terminated sulfopolyurethane/urea, a polyisocyanate, an isocyanate-terminated polyurethane/urea, and a compound selected from the group consisting of water and a polyol or polyamine plus a blowing agent.
None of the technologies discussed above provide a polyurethane dispersion capable of forming self-supporting films that are minimally tacky and self-adhesive, nor do they suggest the use of these materials in cosmetic formulations.
Therefore, a need exists in the art for a polyurethane dispersion stable in water and water-alcohol solvent systems, where the dispersion has one or more of the following properties: minimal tack and high self-adhesion, capable of forming stable dispersions in water and water-alcohol systems, and capable of rapidly forming films on skin or hair by simple ambient evaporation.
The present invention relates to stable aqueous colloidal dispersions of sulfonated polyurethane ureas and films formed from these dispersions.
In brief summary, sulfonated polyurethane ureas of the present invention comprise the reaction product of:
(a) one or more sulfonated polyols;
(b) one or more non-sulfonated polyols;
(c) one or more aliphatic polyisocyanates, having 2 to 25 carbon atoms, or cycloaliphatic polyisocyanates, having 3 to 25 carbon atoms; and
(d) excess water,
wherein the reaction product of (a), (b), and (c) with (d) comprises a polyurea segment of the following formula: 
wherein z is an integer from 0 to 6 and R3 is an aliphatic group, having 2 to 25 carbon atoms, or a cycloaliphatic group, having 3 to 25 carbon atoms, derived from the aliphatic or cycloaliphatic polyisocyanate. The reaction of (a), (b), and (c) forms an isocyanate terminated prepolymer mixture that has an isocyanate to hydroxyl ratio of 1.3 to 2.5:1. Excess water means that the water is in an amount greater than the amount of isocyanate terminated prepolymer mixture (w/w) such that a final aqueous dispersion of less than 50% solids is achieved. The reaction product of (a), (b) and (c) with (d) provides a sulfonated polyurethane urea that has a sulfonate equivalent weight of from about 1000 to about 8500 and that has been chain-extended only with water.
Another aspect of the present invention relates to stable aqueous dispersions prepared from the sulfonated polyurethane ureas described above.
An additional aspect of the present invention relates to self-supporting films prepared from the sulfonated polyurethane ureas described above. These films are formed with no volatile organic compound emissions and with no post-coating chemical or ionic cross-linking; therefore, the overall processing to form the films is simplified into one step. The films of the present invention are minimally tacky and self-adhesive. Some films of the present invention can also be redispersible in water.
In this application:
xe2x80x9cAliphaticxe2x80x9d means a non-aromatic group, which can be a straight or branched chain alkylene group of 2 to 25 carbon atoms wherein these groups may be optionally substituted, for example, with ether, ester, or cycloaliphatic functional groups.
xe2x80x9cColloidal dispersionxe2x80x9d means a discrete distribution of particles having an average size of less than about 1 micron, typically less than about 500 nanometers, in an aqueous media (water) or in a water-alcohol media.
xe2x80x9cCohesivexe2x80x9d means having auto-adhesion or self-adhesion, i.e., the capability of adhering to itself.
xe2x80x9cCycloaliphaticxe2x80x9d means a non-aromatic, optionally substituted cyclic group of 3 to 25 carbons, wherein one to three carbon atoms may be optionally replaced with a heteroatom, for example, nitrogen or oxygen, or C(O). The cycloaliphatic group may be optionally substituted, for example, with alkyl, ether, or ester functional groups.
xe2x80x9cMinimally tackyxe2x80x9d means having a relatively low degree of tack, preferably non-tacky. Therefore, minimally tacky includes compositions that are tack free; very, very, low tack; very low tack, and low tack when tested by a xe2x80x9cfinger appealxe2x80x9d test. The finger appeal test involves qualitatively assessing an adhesive by a light touch and short contact time at room temperature (about 20xc2x0 to 30xc2x0 C.) and assigning a value of 1 through 5, where 1=tack free, 1.25=very, very, low tack, 1.5=very low tack, 2=low tack, 2.5=low-to-medium tack, 3=medium tack, 3.5=medium-to-good tack, 4=good tack, and 5=excellent tack. On this scale, Scotch(trademark) Magic(trademark) transparent tape from Minnesota Mining and Manufacturing Co. (3M), St. Paul, Minn., USA has a rating of 5.
xe2x80x9cPolyureaxe2x80x9d means a polymer obtained by a polymerization reaction in which the mechanism of chain growth is entirely the formation of urea and biuret linkages by the reaction of isocyanate groups with amine or urea groups, with urea linkage formation predominating.
xe2x80x9cSelf-adhesionxe2x80x9d means a material preferentially adheres to itself or a chemically similar material under pressure or force without the need for significantly elevated temperatures (e.g., without the need for temperatures above about 50xc2x0 C.). Preferred compositions of the invention exhibit self-adhesion properties immediately upon contact to itself at room temperature (about 20xc2x0 to 30xc2x0 C.). As used in the previous sentence, the term xe2x80x9cimmediatelyxe2x80x9d means less than a few minutes, e.g., about 5 minutes, preferably less than 1 minute, more preferably less than 30 seconds, depending on the application.
xe2x80x9cStable aqueous colloidal dispersionxe2x80x9d means a uniform dispersion of polymer particles having an average diameter of from about 10 nanometers to about 1 micron in water, which do not agglomerate in the absence of agitation (either continuous or intermittent).
xe2x80x9cSulfonate equivalent weightxe2x80x9d means the sum of the atomic weights of all of the atoms in the sulfopolyurea divided by the number of sulfonate groups contained in the polymer molecule.
xe2x80x9cSulfopolyureaxe2x80x9d means a high molecular weight polyurea containing at least one sulfonate group covalently bonded to and pendant from the polymer chain.
xe2x80x9cSulfonated polyurethane ureaxe2x80x9d refers to a polymer containing sulfonate groups and a plurality of urea linkages and urethane linkages.
The sulfonated polyurethane ureas of the present invention comprise the reaction product of: (a) one or more sulfonated polyols, (b) one or more non-sulfonated polyols, (c) one or more aliphatic or cycloaliphatic polyisocyanates, and (d) excess water, wherein the reaction product of (a), (b), and (c) with (d) comprises a polyurea segment of the following formula: 
wherein z is an integer from 0 to 6 and R3 is an aliphatic group, having 2 to 25 carbon atoms, or a cycloaliphatic group, having 3 to 25 carbon atoms, derived from the aliphatic or cycloaliphatic polyisocyanate. The reaction of (a), (b), and (c) forms an isocyanate terminated prepolymer mixture that has an isocyanate to hydroxyl ratio (NCO/OH) of 1.3 to 2.5:1. The reaction product of (a), (b) and (c) with (d) provides a sulfonated polyurethane urea that has a sulfonate equivalent weight of from about 1000 to about 8500 and that has been chain-extended only with water.
The term xe2x80x9cpolyolxe2x80x9d as used herein refers to polyhydric alcohols comprising two or more hydroxyl groups. The polyols can be hydrophilic or hydrophobic. The term xe2x80x9cpolyolxe2x80x9d as used herein includes non-sulfonated polyols and non-sulfonated polyols used in the preparation of sulfonated polyols. A non-sulfonated polyol is a polyol that does not contain a sulfonate group pendant from the polyol backbone.
A preferred class of polyols suitable for use in the present invention includes polyols having molecular weights in the range of from about 200 to about 2000. Preferably, the polyols contain divalent aliphatic or cycloaliphatic groups containing ether or ester functional groups. Also, mixtures of polyols can be used.
Polyols suitable for use in the present invention can be selected from the group consisting of polyether polyols, polyester polyols, polycaprolactone polyols, polytetramethylene glycols, and the like, and mixtures thereof. Additionally, polyester diols made from diesters, diacids, and diols may be utilized. Diesters and diacids useful for making polyester diols include, but are not limited to, dimethyl isophthalate, dimethyl terephthalate, and dimethyl adipate, and the like; diols useful for making polyester diols include propylene glycol, 1,3-propane diol, 1,4-butane diol, and the like.
Polyols of the present invention include, but not limited to, polyethylene glycols and polypropylene glycols. In addition, polyols of the present invention include, but are not limited to, diethylene glycol/adipic acid polyester polyol (Lexorez(trademark) 1100-220, available from Inolex Chemical Company, Philadelphia, Pa.); neopentyl glycol, 1,6-hexanediol, isophthalate, adipate polyester polyol (Fomrez(trademark) 8056-146, available from Witco Corp., New York, N.Y.); 400 average molecular weight polyethylene glycol (available from DuPont Chemicals, Wilmington, Del.), 600 average molecular weight polyethylene glycol (available from Union Carbide Chemical and Plastics Co., Inc., Danbury, Conn.); 1000 average molecular weight polypropylene glycol (available from Arco Chemical, Newton Square, Pa.), 1000 average molecular weight polyethylene glycol (available from Union Carbide Chemical and Plastics Co., Inc., Danbury, Conn.); 3400 average molecular weight polyethylene glycol (available from Aldrich Chemical Company, Milwaukee, Wis.) and polycaprolactone diol (Tone(trademark)-200, available from Union Carbide Corp.).
A sulfonated polyol is a polyol that contains at least one sulfonate group (SO3M where M is a cation selected from the group consisting of the alkali metal cations Na+, Li+, and K+) pendant from the polyol backbone. Sulfonated polyols can be made from non-sulfonated polyols by a transesterification or esterification reaction.
A preferred class of sulfonated polyols are prepared under typical transesterification or esterification reaction conditions, using one or more of the polyols indicated above, other diols, or combinations of the polyols and other diols with dimethyl-5-sodiosulfoisophthalate (DMSSIP CAS #3965-55-7, commercially available from Aldrich Chemical Company, Milwaukee, Wis.) or 5-sodiosulfoisophthalic acid (SSIP CAS #6362-79-4, commercially available from Aldrich Chemical Company, Milwaukee, Wis.), and a transesterification reaction catalyst (for example, tetrabutyl titanate, commercially available from Aldrich Chemical Company, Milwaukee, Wis.). Typically an excess of the polyol (up to as much as a 4:1 molar excess polyol relative to dimethyl-5-sodiosulfoisophthalate) is used in the formation of the sulfonated polyol. When the reaction is complete, the product is a mixture of sulfonated polyols and non-sulfonated polyols.
A variety of polyols may be utilized. Polyols of the present invention include, but not limited to, 400 average molecular weight polyethylene glycol (available from DuPont Chemicals, Wilmington, Del.), 600 average molecular weight polyethylene glycol (available from Union Carbide Chemical and Plastics Co., Inc., Danbury, Conn.), 425 average molecular weight polypropylene glycol (available from Arco Chemical, Newton Square, Pa.), and 300 average molecular weight polyethylene glycol (available from Aldrich Chemical Company, Milwaukee, Wis.). Also mixtures of polyols can be used. A preferred polyol is a mixture of polyethylene glycol with a hydroxy equivalent weight of 200 and polypropylene glycol with a hydroxy equivalent weight of 212. The result of reaction of about 4 equivalents of the polyol mixture above per equivalent of DMSSIP produces a sulfonated polyol having a hydroxy equivalent weight of about 300 and a centrally located aromatic sulfonate group.
Other polyols that may be reacted with DMSSIP, in order to provide a sulfonated polyol useful in the present invention, include polycaprolactone polyols. Additionally, dimethyl-5-sodiosulfoisophthalate or 5-sodiosulfoisophthalic acid may be utilized with other diesters of diacids, including dimethyl isophthalate, dimethyl terephthalate and dimethyl adipate, and diols to produce co-polyester diols containing sulfonate. Examples of such diols include propylene glycol; 1,3-propane diol; 1,4-butane diol; 1,5-pentane diol; 1,6-hexane diol; neopentyl glycol; diethylene glycol; dipropylene glycol; 2,2,4-trimethyl- 1,3 pentane diol; 1,4-cyclohexanedimethanol; ethylene oxide and/or propylene oxide adduct of bisphenol A; ethylene oxide and/or propylene oxide adduct of hydrogenated bisphenol A; polyethylene glycol and polypropylene glycol.
Polyisocyanates used in the preparation of the sulfonated polyurethane ureas of the present invention are aliphatic or cycloaliphatic polyisocyanates and mixtures thereof. A wide variety of aliphatic and cycloaliphatic polyisocyanates may be utilized. Polyisocyanates of the present invention are any aliphatic and/or cycloaliphatic organic compounds that have two or more reactive isocyanate (i.e. xe2x80x94NCO) groups in a single molecule. This definition includes diisocyanates, triisocyanates, tetraisocyanates, etc., and mixtures thereof. A particularly well-known and useful class of polyisocyanates are diisocyanates.
Suitable polyisocyanates include, but are not limited to, isophorone diisocyanate, (IPDI), commercially available from Bayer Corp., Pittsburgh, Pa. as Desmodur(trademark) I, bis(4-isocyanatocyclohexyl)methane (H12MDI), commercially available from Bayer Corp. as Desmodur(trademark) W, trimethyl-1,6-diisocyanatohexane (TMDI, available from Aldrich Chemical Company, Milwaukee, Wis.; (CAS #34992-02-4)), 1,6-diisocyanatohexane (HDI, available from Aldrich Chemical Company, Milwaukee, Wis.(CAS #822-06-0)), and mixtures thereof.
Excess water means that the water is in an amount greater than the amount of isocyanate terminated prepolymer mixture (w/w) such that a final aqueous dispersion of less than 50% solids is achieved. Water is also used to chain extend the prepolymer mixture.
In the sulfonated polyurethane urea of the present invention, at least one sulfonate group (SO3M) is pendant from the sulfonated polyurethane urea backbone. Preferably the SO3M group is pendant from an aromatic moiety incorporated into the sulfonated polyurethane urea. The sulfonate group within the polyurethane urea backbone is derived from the sulfonated polyol described above. The sulfonated polyurethane urea has a sulfonate group equivalent weight of from about 1000 to 8500, preferably about 3000 to 6000.
The sulfonated polyurethane urea polymer backbone is a polymer that contains a plurality of urethane segments and a plurality of urea segments. The urethane segments are derived from the reaction of sulfonated polyols, non-sulfonated polyols and aliphatic and/or cycloaliphatic polyisocyanates to form an isocyanate terminated prepolymer mixture. The urea segments of the polymer are derived from the reaction of the isocyanate terminated prepolymer mixture with water.
The amount of urea segments to urethane segments in the sulfonated polyurethane urea is critical in determining the physical properties of a film formed from the aqueous dispersions of sulfonated polyurethane ureas of the present invention. The urea segments reduce tackiness of the sulfonated polyurethane urea, and the urethane segments promote self-adhesion. Therefore, to achieve a minimally tacky, self-adhesive film, the amount of urea segments to urethane segments must be properly balanced.
The amount of urea segments to urethane segments arises from the isocyanate to hydroxyl ratio (NCO/OH) of the isocyanate terminated prepolymer, a higher ratio indicating more free isocyanate. Therefore, the isocyanate to hydroxyl ratio (NCO/OH) of the isocyanate terminated prepolymer mixture ultimately determines the molecular weight and physical properties of the sulfonated polyurethane urea generated. Preferably a NCO/OH ratio of about 1.3 to 2.5:1, more preferably about 1.65 to 1.85:1, and most preferably about 1.75:1, is used to generate an isocyanate terminated prepolymer average molecular weight of about 700 to 2500, more preferably about 1200 to 1700. If the average molecular weight of the isocyanate terminated prepolymer mixture is too high, the prepolymer mixture becomes too viscous; therefore, this molecular weight range is preferred.
When the NCO/OH ratio is about 1.3 to 2.5:1, the resulting sulfonated polyurethane ureas have a combination of urea and urethane segments such that films formed from the dispersions of sulfonated polyurethane ureas are surprisingly self-supporting, minimally tacky, and self-adhesive, i.e. the film has a minimally tacky feel when touched, and at the same time has the capability to adhere to itself. In addition, these films can also be water-redispersible. When the NCO/OH ratio is about 1.65 to 1.85:1 and more preferably about 1.75:1, the amount of urea segments to urethane segments in the sulfonated polyurethane urea is even more evenly balanced to provide a film that is minimally tacky and self-adhesive.
When the ratio NCO/OH is too high, the resulting sulfonated polyurethane urea has too many urea segments and too few urethane segments and a film formed from an aqueous dispersion of sulfonated polyurethane urea will tend to not have self-adhesive properties. Furthermore, it has been discovered that when the NCO/OH ratio is too low, the resulting sulfonated polyurethane urea has too many urethane groups and too few urea groups, and a film formed from a dispersion of sulfonated polyurethane urea will tend to be tacky when touched and not self-supporting.
Preparation of the sulfonated polyurethane ureas of the present invention is schematically depicted in the following Scheme A: 
In Step 1 of Scheme A, a transesterification or esterification reaction is performed in which a compound of formula (I), wherein R is H or CH3, is reacted with a polyol (IIa) in the presence of a catalyst. Within the polyol (IIa), R1 is a divalent aliphatic group having an average molecular weight of 200 to 2000 comprising ether or ester functional groups. This reaction provides a sulfonated polyol (III) and unreacted/excess polyol (IIa). Suitable catalysts include, for example, tetrabutyl titanate (TBT), zinc chloride, sodium alkoxides, cadmium acetate, and lead acetate. The transesterification or esterification reaction is performed at approximately 170xc2x0 C. Polyol (IIa) may be a single polyol or a mixture of polyols, producing a single sulfonated polyol (III) or a mixture of sulfonated polyols (III).
In Step 2, sulfonated polyol (III), polyol (IIa), and optionally polyol (IIb) are reacted with polyisocyanate (IV). Within the polyisocyanate (IV), R3 is as defined previously, and within the polyol (IIb), R2 is a divalent aliphatic group or cycloaliphatic group having a molecular weight of 200 to 2,000 comprising ether or ester functional groups. This reaction provides isocyanate terminated prepolymer (V) and (VI) and unreacted/excess polyisocyanate (IV). In this Step additional polyol (IIa) and/or a different polyol (IIb) may be added. Polyol (IIa) and (IIb) may be a single polyol or a mixture of polyols and polyisocyanate (IV) may be a single polyisocyanate or a mixture of polyisocyanates. The isocyanate terminated prepolymer (V) and (VI) is comprised of the reaction products of polyisocyanate (IV) with any one or combination of sulfonated polyol (III), polyol (IIa) and polyol (IIb). Therefore, the end-product of Step 2 comprises an isocyanate terminated prepolymer mixture that is a mixture of isocyanate terminated sulfonated prepolymer (V), isocyanate terminated prepolymer (VI), and excess polyisocyanate (IV). The isocyanate terminated sulfonated prepolymer (V) produced by the above described process is described in U.S. Pat. Nos. 4,558,149, 4,746,717, and 4,855,384, which are incorporated herein by reference in their entirety.
In Step 3, the isocyanate terminated prepolymer mixture, [(V), (VI) and (IV)], is mixed with excess water pre-heated to approximately 50-65xc2x0 C. with sufficient agitation to avoid macroscopic gel formulation. This addition produces an aqueous colloidal dispersion of sulfonated polyurethane urea (VII). Excess water means that the amount of water is greater than the amount of isocyanate terminated prepolymer mixture (w/w). Within the sulfonated polyurethane urea (VII), U is a polyurea segment of the following formula: 
wherein R3 is derived from the polyisocyanate (IV) and is as defined previously and z is as defined previously. The reaction may be stirred at approximately 75xc2x0 C. for 1-3 hours. Mixing methods may be employed that provide adequate levels of shear or agitation in order to avoid formation of macroscopic gel particles.
Chain extension is accomplished with water only; chain extension with a diamine (H2Nxcx9cNH2) does not provide minimally tacky, self-adhesive properties. Co-solvents, such as volatile organic compounds, are not required. Therefore, exposure to and disposal of potentially harmful volatile organic chemicals can be eliminated.
Subsequent to being introduced into the aqueous environment, a portion of the isocyanate groups react with water to form amino groups and CO2. These amino groups spontaneously react with another isocyanate group to form urea linkages in the sulfonated polyurethane ureas.
This process produces a discreet aqueous distribution or aqueous dispersion of sulfonated polyurethane urea particles less than one micron in diameter, typically ranging from about 10 nanometers to about 500 nanometers in diameter. The dispersions can have a translucent, bluish appearance characteristic of a colloidal dispersion or can range from a clear light yellow solution to a milky white dispersion. The particles have sufficient hydrophilicity imparted to them by the pendant sulfonate groups that the dispersion displays good stability, showing substantially no agglomeration in the absence of stirring or agitation under extended storage at ambient conditions without supplemental surfactants. Supplemental surfactants do not need to be added to the dispersions to facilitate wetting various substrates. Therefore, the dispersions of the present invention contain no additives to affect dispersion stability.
Free standing or self-supporting films are readily prepared from the aqueous colloidal dispersions by removing water from the composition and allowing the films to dry. Conventional spin casting or film coating techniques can be utilized to form these films. Organic co-solvents are not required to facilitate film formation and/or wetting of substrates. Although co-solvents are not required, as one skilled in the art would understand, alcohols can be added to the aqueous dispersion after formation of the sulfonated polyurethane urea to provide a water-alcohol system. A water-alcohol system may be preferred in certain applications to provide, for example, faster drying time, and in other applications an aqueous system may be preferred to provide, for example, essentially no volatile organic compound (VOC) emissions. After drying free-standing or self-supporting films are formed. These films are minimally tacky and self-adhesive. In addition, some of the films can be redispersed in water.
The colloidal dispersions of sulfonated polyurethane ureas and films of the present invention may be used in a variety of applications including, for example, cohesive tapes, sealing materials, nonwoven binder, fluorochemical flexibilizers/softener, ink receptive coatings, polyolefin primer, and cosmetic applications. The sulfonated polyurethane ureas and films formed therefrom may be used in any application where a minimally tacky, self-adhering material is desirable. In addition, some of the films of the present invention are also water redispersible; therefore, they may be used in any application where a minimally tacky, self-adhering and water redispersible material is desired, including for example, water-soluble adhesives.
In addition, the inventive composition and films formed therefrom are useful in cosmetic applications. Such applications require some amount of water resistance, transfer resistance, or substantivity to skin, nails or hair. The applications include, e.g., makeup cosmetic or protective cosmetic applications such as mascara, foundation, rouge, face powder, eyeliner, eyeshadow, insect repellent, nail polish, skin moisturizer, skin cream and body lotion, lipstick, and sunscreen.
When the inventive dispersion is used in hair care products, such as shampoos and conditioners and the like, the dispersion can provide faster drying. It can also improve the humidity resistance of hair styling agents when used at low levels in combination with other hair styling resins. The hair care products, as described herein, are not xe2x80x9creshapablexe2x80x9d hair styling compositions. xe2x80x9cReshapablexe2x80x9d hair styling composition means a hair styling composition providing hair styling that can be restored or modified without new material or heat being applied. For example, in order to restore or modify the hairstyle in case of xe2x80x9cdroopingxe2x80x9d or loss of setting (dishevelment), no new materials, such as water or any form of fixing agent, or heat are required. The composition can be long lasting, such as 10-24 hours, giving rise to a durable styling effect.
The dispersions and films of the present invention may be coated upon a variety of flexible and inflexible substrates using conventional coating techniques to produce sheet materials coated with a sulfonated polyurethane urea film. Flexible substrates are defined herein as any material which is conventionally utilized as a tape backing or may be of any other flexible material. Illustrative examples include, but are not limited to, paper, plastic films such as polypropylene, polyethylene, polyvinyl chloride, polyester (polyethylene terephthalate), polycarbonate, poly(methyl methacrylate) (PMMA), cellulose acetate, cellulose triacetate, and ethyl cellulose. Additionally, flexible substrates include, but are not limited to, woven fabric formed of threads of synthetic or natural materials such as cotton, wool, nylon, rayon, glass, or ceramic material, or they may be nonwoven fabric such as air-laid webs of natural or synthetic fibers or blends of these. Illustrative examples of inflexible substrates include, but are not limited to, metal, metallized polymeric film, or ceramic sheet material. The dispersions and films can also be applied to fibrous substrates of synthetic or natural materials, such as keratin and collagen.
The coated sheet materials may take the form of any article conventionally known to be utilized with minimally tacky, self-adhesive compositions such as labels, tapes, signs, covers, marking indices, and the like.